1.5.5 and 1.5.6 upgrade issue for Advanced Shipper addon Users

Users of Advanced Shipper:

When doing your upgrade from 1.5.4 or lower to 1.5.5 or higher, you might get stuck in zc_install with the log

[11-Feb-2019 09:23:52 America/New_York] MySQL error 1406 encountered during zc_install:
Data too long for column 'shipping_method' at row 12270
ALTER TABLE orders MODIFY shipping_method VARCHAR(255) NOT NULL DEFAULT '';

Your symptom will be the message in zc_install which will be something like:
"Cannot upgrade to 1.5.6; your database must be updated to 1.5.5 first."

Your best bet is probably to remove the check in includes/systemChecks.yml (line 299-303).

This issue was originally reported here:
https://www.zen-cart.com/showthread....1-5-3-to-1-5-6

I'm just adding this thread to help people searching for this problem.

Thanks. Appreciated.

This issue has been resolved by PR #3226.
https://github.com/zencart/zencart/pull/3226

Users upgrading from 1.5.4 or below can pull this in to their copy of 1.5.6, or wait for 1.5.7, which will include this fix.

Update (several years later): this allows the upgrade to complete but creates an upgrade debug log.
For users upgrading through 1.5.5 or 1.5.6 to a newer version of Zen Cart who have Advance Shipper installed, it might be best to comment out

ALTER TABLE orders MODIFY shipping_method VARCHAR(255) NOT NULL DEFAULT '';

in

zc_install/sql/updates/mysql_upgrade_zencart_156.sql
zc_install/sql/updates/mysql_upgrade_zencart_155.sql

If you have entries in the shipping_method column that are too long for the ALTER TABLE to work.